Merge pull request #31 from tobrun/kdz-new-functionality

kiryldz · web-flow · commit bb7d1dc08bf8 · 2023-03-07T10:58:21.000+02:00
Additional functionality
diff --git a/README.md b/README.md
@@ -28,8 +28,8 @@ And you will have to include the required dependencies:
 
 ```groovy
 dependencies {
-  implementation 'com.github.tobrun.kotlin-data-compat:annotation:0.1.0'
-  ksp 'com.github.tobrun.kotlin-data-compat:processor:0.1.0'
+  implementation 'com.github.tobrun.kotlin-data-compat:annotation:0.3.0'
+  ksp 'com.github.tobrun.kotlin-data-compat:processor:0.3.0'
 }
 ```
 
@@ -39,7 +39,10 @@ dependencies {
 Given an exisiting data class:
  - add `@DataCompat` annotation
  - mark class private
- - Append `Data` to the class name
+ - append `Data` to the class name
+ - support default parameters by using `@Default` annotation
+ - retain existing class annotations (but not parameters for them)
+ - retain existing interfaces
 
 For example:
 
@@ -57,101 +60,120 @@ private data class PersonData(val name: String, val nickname: String? = null, va
 After compilation, the following class will be generated:
 
 ```kotlin
+package com.tobrun.`data`.compat.example
+
+import java.util.Objects
+import kotlin.Any
+import kotlin.Boolean
+import kotlin.Int
+import kotlin.String
+import kotlin.Unit
+import kotlin.jvm.JvmSynthetic
+
 /**
  * Represents a person.
  * @property name The full name.
  * @property nickname The nickname.
  * @property age The age.
  */
+@SampleAnnotation
 public class Person private constructor(
-  public val name: String,
-  public val nickname: String?,
-  public val age: Int
-) {
-  public override fun toString() = "Person(name=$name, nickname=$nickname, age=$age)"
-
-  public override fun equals(other: Any?): Boolean = other is Person
-  		&& name == other.name
-  		&& nickname == other.nickname
-  		&& age == other.age
-
-  public override fun hashCode(): Int = Objects.hash(name, nickname, age)
-
-  /**
-   * Composes and builds a [Person] object.
-   *
-   * This is a concrete implementation of the builder design pattern.
-   *
-   * @property name The full name.
-   * @property nickname The nickname.
-   * @property age The age.
-   */
-  public class Builder {
-    @set:JvmSynthetic
-    public var name: String? = null
-
-    @set:JvmSynthetic
-    public var nickname: String? = null
-
-    @set:JvmSynthetic
-    public var age: Int? = null
-
-    /**
-     * Set the full name.
-     *
-     * @param name the full name.
-     * @return Builder
-     */
-    public fun setName(name: String?): Builder {
-      this.name = name
-      return this
+    public val name: String,
+    public val nickname: String?,
+    public val age: Int
+) : SampleInterface {
+    public override fun toString() = """Person(name=$name, nickname=$nickname,
+      age=$age)""".trimIndent()
+
+    public override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+        other as Person
+        return name == other.name && nickname == other.nickname && age == other.age
     }
 
-    /**
-     * Set the nickname.
-     *
-     * @param nickname the nickname.
-     * @return Builder
-     */
-    public fun setNickname(nickname: String?): Builder {
-      this.nickname = nickname
-      return this
-    }
+    public override fun hashCode(): Int = Objects.hash(name, nickname, age)
 
     /**
-     * Set the age.
-     *
-     * @param age the age.
-     * @return Builder
+     * Convert to Builder allowing to change class properties.
      */
-    public fun setAge(age: Int?): Builder {
-      this.age = age
-      return this
-    }
+    public fun toBuilder(): Builder = Builder() .setName(name) .setNickname(nickname) .setAge(age)
 
     /**
-     * Returns a [Person] reference to the object being constructed by the builder.
+     * Composes and builds a [Person] object.
      *
-     * Throws an [IllegalArgumentException] when a non-null property wasn't initialised.
+     * This is a concrete implementation of the builder design pattern.
      *
-     * @return Person
+     * @property name The full name.
+     * @property nickname The nickname.
+     * @property age The age.
      */
-    public fun build(): Person {
-      if (name==null) {
-      	throw IllegalArgumentException("Null name found when building Person.")
-      }
-      if (age==null) {
-      	throw IllegalArgumentException("Null age found when building Person.")
-      }
-      return Person(name!!, nickname, age!!)
+    public class Builder {
+        @set:JvmSynthetic
+        public var name: String? = "John"
+
+        @set:JvmSynthetic
+        public var nickname: String? = null
+
+        @set:JvmSynthetic
+        public var age: Int? = 42
+
+        /**
+         * Set the full name.
+         *
+         * @param name the full name.
+         * @return Builder
+         */
+        public fun setName(name: String?): Builder {
+            this.name = name
+            return this
+        }
+
+        /**
+         * Set the nickname.
+         *
+         * @param nickname the nickname.
+         * @return Builder
+         */
+        public fun setNickname(nickname: String?): Builder {
+            this.nickname = nickname
+            return this
+        }
+
+        /**
+         * Set the age.
+         *
+         * @param age the age.
+         * @return Builder
+         */
+        public fun setAge(age: Int?): Builder {
+            this.age = age
+            return this
+        }
+
+        /**
+         * Returns a [Person] reference to the object being constructed by the builder.
+         *
+         * Throws an [IllegalArgumentException] when a non-null property wasn't initialised.
+         *
+         * @return Person
+         */
+        public fun build(): Person {
+            if (name==null) {
+                throw IllegalArgumentException("Null name found when building Person.")
+            }
+            if (age==null) {
+                throw IllegalArgumentException("Null age found when building Person.")
+            }
+            return Person(name!!, nickname, age!!)
+        }
     }
-  }
 }
 
 /**
  * Creates a [Person] through a DSL-style builder.
  *
- * @param initializer the intialisation block
+ * @param initializer the initialisation block
  * @return Person
  */
 @JvmSynthetic
diff --git a/annotation/src/main/kotlin/com/tobrun/datacompat/annotation/Default.kt b/annotation/src/main/kotlin/com/tobrun/datacompat/annotation/Default.kt
@@ -0,0 +1,16 @@
+package com.tobrun.datacompat.annotation
+
+/**
+ * Default value represented as a String.
+ * Workaround for KSP not supporting class default parameters:
+ * https://github.com/google/ksp/issues/642
+ *
+ * Could be applied only for passing default values in the [DataCompat] class.
+ *
+ * @param valueAsString exact representation of the default value. E.g. if default [String] is used,
+ *  it should be passed here as "\"STRING_VALUE\""; if default [Int] is used, it should be passed
+ *  as "INT_VALUE".
+ */
+@Retention(AnnotationRetention.RUNTIME)
+@Target(AnnotationTarget.VALUE_PARAMETER)
+annotation class Default(val valueAsString: String)
diff --git a/example/src/main/kotlin/com/tobrun/data/compat/example/PersonData.kt b/example/src/main/kotlin/com/tobrun/data/compat/example/PersonData.kt
@@ -1,6 +1,10 @@
 package com.tobrun.data.compat.example
 
 import com.tobrun.datacompat.annotation.DataCompat
+import com.tobrun.datacompat.annotation.Default
+
+interface SampleInterface
+annotation class SampleAnnotation
 
 /**
  * Represents a person.
@@ -9,4 +13,11 @@ import com.tobrun.datacompat.annotation.DataCompat
  * @property age The age.
  */
 @DataCompat
-private data class PersonData(val name: String, val nickname: String? = null, val age: Int)
+@SampleAnnotation
+private data class PersonData(
+    @Default("\"John\"")
+    val name: String,
+    val nickname: String?,
+    @Default("42")
+    val age: Int
+) : SampleInterface
diff --git a/processor/src/main/kotlin/com/tobrun/datacompat/DataCompatProcessor.kt b/processor/src/main/kotlin/com/tobrun/datacompat/DataCompatProcessor.kt
@@ -29,6 +29,7 @@ import com.squareup.kotlinpoet.ksp.toTypeName
 import com.squareup.kotlinpoet.ksp.toTypeParameterResolver
 import com.squareup.kotlinpoet.ksp.writeTo
 import com.tobrun.datacompat.annotation.DataCompat
+import com.tobrun.datacompat.annotation.Default
 import java.util.Locale
 
 /**
@@ -187,18 +188,46 @@ class DataCompatProcessor(
                         .returns(Int::class)
                         .build()
                 )
+
+                // Function toBuilder
+                addFunction(
+                    FunSpec.builder("toBuilder")
+                        .addKdoc(
+                            """
+                            Convert to Builder allowing to change class properties.
+                            """.trimIndent()
+                        )
+                        .addStatement(
+                            propertyMap.keys.joinToString(
+                                prefix = "return Builder() .",
+                                transform = { str ->
+                                    "set${str.toString().replaceFirstChar {
+                                        if (it.isLowerCase())
+                                            it.titlecase(Locale.getDefault())
+                                        else it.toString()
+                                    }}($str)"
+                                },
+                                separator = " .",
+                            )
+                        )
+                        .returns(ClassName("", "Builder"))
+                        .build()
+                )
             }
 
             // Builder pattern
             val builderBuilder = TypeSpec.classBuilder("Builder")
             for (property in propertyMap) {
                 val propertyName = property.key.toString()
+                val defaultValue = property.key.annotations
+                    .firstOrNull { it.annotationType.resolve().toString() == Default::class.simpleName }
+                    ?.arguments?.first()
                 val nullableType = property.value.copy(nullable = true)
                 builderBuilder.addProperty(
                     PropertySpec.builder(propertyName, nullableType)
                         .initializer(
                             CodeBlock.builder()
-                                .add("null")
+                                .add((defaultValue?.value as? String?) ?: "null")
                                 .build()
                         )
                         .addAnnotation(
diff --git a/processor/src/test/kotlin/com/tobrun/datacompat/DataCompatProcessorTest.kt b/processor/src/test/kotlin/com/tobrun/datacompat/DataCompatProcessorTest.kt
@@ -14,6 +14,7 @@ private val simpleTest = SourceFile.kotlin(
     "PersonData.kt",
     """
 import com.tobrun.datacompat.annotation.DataCompat
+import com.tobrun.datacompat.annotation.Default
 
 interface EmptyInterface
 interface EmptyInterface2
@@ -27,8 +28,11 @@ interface EmptyInterface2
 @Deprecated
 @DataCompat
 private data class PersonData(
+    @Default("\"John\"")
     val name: String,
-    val nickname: String? = null,
+    @Default("null")
+    val nickname: String?,
+    @Default("23")
     val age: Int,
     val veryLongAndVeryDetailedDescription: String?
 ) : EmptyInterface, EmptyInterface2
diff --git a/processor/src/test/kotlin/com/tobrun/datacompat/SimpleTestContent.kt b/processor/src/test/kotlin/com/tobrun/datacompat/SimpleTestContent.kt
@@ -37,6 +37,12 @@ internal val expectedSimpleTestContent = """
     
       public override fun hashCode(): Int = Objects.hash(name, nickname, age,
           veryLongAndVeryDetailedDescription)
+
+      /**
+       * Convert to Builder allowing to change class properties.
+       */
+      public fun toBuilder(): Builder = Builder() .setName(name) .setNickname(nickname) .setAge(age)
+          .setVeryLongAndVeryDetailedDescription(veryLongAndVeryDetailedDescription)
     
       /**
        * Composes and builds a [Person] object.
@@ -50,13 +56,13 @@ internal val expectedSimpleTestContent = """
        */
       public class Builder {
         @set:JvmSynthetic
-        public var name: String? = null
+        public var name: String? = "John"
     
         @set:JvmSynthetic
         public var nickname: String? = null
     
         @set:JvmSynthetic
-        public var age: Int? = null
+        public var age: Int? = 23
 
         @set:JvmSynthetic
         public var veryLongAndVeryDetailedDescription: String? = null
diff --git a/processor/src/test/kotlin/com/tobrun/datacompat/TestAnnotation.kt b/processor/src/test/kotlin/com/tobrun/datacompat/TestAnnotation.kt
@@ -10,5 +10,9 @@ package com.tobrun.datacompat.annotation
 @Retention(AnnotationRetention.RUNTIME)
 @Target(AnnotationTarget.CLASS)
 annotation class DataCompat
+
+@Retention(AnnotationRetention.RUNTIME)
+@Target(AnnotationTarget.CLASS)
+annotation class Default(val valueAsString: String)
     """.trimIndent()
 )
